In fact, dangerous bacteria may not always look or smell particularly bad.

Moir states in The Conversation that: “pathogenic (disease-causing) bacteria, such as salmonella, campylobacter, E.coli and listeria, which do make people sick, don’t always cause obvious changes in food when they grow.”

“Sometimes simply being present at low numbers and then consumed is enough to result in illness,” Moir said.

However, there are other ways to check if your food has gone off.

Moir advised people to “observe ‘use by’ dates, refrigerate foods that need to be kept cold (this slows down the microbes), cook foods properly (this kills the microbes) and prevent contact and cross contamination between ready-to-eat foods such as salads, with raw food such as meat that still needs to be cooked.”